When it comes to Major League Baseball’s pitchers, the more strikes, the better. But what if white umpires call strikes more often for white pitchers than for minority pitchers?

New research findings provide an answer. Analysis of 3.5 million pitches from 2004 to 2008 found that minority pitchers scale back their performance to overcome racial/ethnic favoritism toward whites by MLB home plate umpires, says financial economist Johan Sulaeman of SMU’s Cox School of Business, one of the study’s authors.

The study found that minority pitchers reacted to umpire bias by playing it safe with the pitches they throw in a way that actually harmed their performance and statistics, said Sulaeman, a labor and discrimination expert.

Specifically, minority pitchers limited the umpires’ discretion to call their pitch a “ball” by throwing squarely across the plate in the strike zone more often. Unfortunately for the pitcher, such throws are also easier for batters to hit.

The finding builds on an earlier study that discovered Major League Baseball’s home plate umpires called strikes more often for pitchers in their same ethnic group – except when the plate was electronically monitored by cameras, Sulaeman said.

While the earlier finding surprised the researchers, they said, the latest results are even more surprising.

Since most MLB umpires are white, the overall effect is that umpire bias pushes performance measures of minorities downward, said Sulaeman, an expert in labor economics and discrimination.

The findings have important implications for measuring the extent of discrimination not only in baseball, but also in labor markets generally, say the authors.

“In MLB, as in so many other fields of endeavor, power belongs disproportionately to members of the majority – white – group,” the authors write.

In addition to Sulaeman, co-authors were Christopher A. Parsons, University of North Carolina at Chapel Hill; Michael C. Yates, Auburn University; and Daniel S. Hamermesh, University of Texas at Austin.